Vibrating gyroscope

ABSTRACT

A vibrating gyroscope having a vibratable body in the form of a triangular prism, piezoelectric elements formed on side surfaces of the vibrating body and having the same vibration characteristics and a detection circuit having two input terminals connected to two of the piezoelectric elements to detect the difference between the outputs from the two piezoelectric elements, the two detection piezoelectric elements being selected such that the difference between their outputs with respect to a change in ambient atmosphere temperature is the smallest.

This is a division of application Ser. No. 08/692,772, filed Aug. 6,1996, now U.S. Pat. No. 5,773,915.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vibrating gyroscope which can be usedfor a navigation system that provides navigational guidance by detectinga rotational angular velocity to detect the position of a moving object,or used for an anti-vibration system, such as a camera-shake preventionapparatus, that prevents the adverse effects of shaking by detecting arotational angular velocity due to external vibration, such as camerashake.

2. Description of the Related Art

FIG. 1 is a perspective view of an essential portion of an example of aconventional vibrating gyroscope, and FIG. 2 is a front view thereof. Asshown in FIGS. 1 and 2, a conventional vibrating gyroscope has avibrator portion 71. The vibrator portion 71 includes a vibrating body73 made of a permanently elastic metal generally in the form of aregular triangular prism. Piezoelectric elements 75a, 75b, 75c, each ofwhich is a thin and generally rectangular member, are bonded to centralportions of side surfaces of the vibrating body 73 with an adhesive. Ofthese piezoelectric elements, the piezoelectric elements 75a, 75b areused for driving and detection while the piezoelectric element 75c isused for feedback. A drive circuit (not shown in FIGS. 1 and 2)consisting of an oscillation circuit and a phase circuit is connectedacross the piezoelectric elements 75a, 75b and the piezoelectric element75c as a feedback loop for causing self-excited vibration of thevibrating body 73. A detection circuit formed of a differentialamplifier, etc. is connected to the piezoelectric elements 75a, 75b.

Two supporting members 77, each of which is a generally square-bottomedU-shaped member formed of a wire rod having a high elastic modulus, arefixed on the ridge line of the vibrating body 73 between the driving anddetecting piezoelectric elements 75a and 75b and in the vicinity ofnodal points of the vibrating body 73. Ends of the supporting members 77are fixed to one major surface of a generally rectangular mount baseplate 79 made of a glass-epoxy material or the like.

In the vibrating gyroscope, if a drive signal is applied across thefeedback piezoelectric element 75c and the driving and detectingpiezoelectric elements 75a, 75b, the vibrating body 73 vibrates under abending mode in a direction perpendicular to the surface on which thefeedback piezoelectric element 75c is formed. In the case where thevibrating body 73 is rotated, the direction of vibration of thevibrating body 73 is changed by the Coriolis force so that a differenceis caused between the outputs from the piezoelectric elements 75a, 75bin response to the rotational angular velocity. This output differenceis processed by signal processing in the detection circuit to detect therotational angular velocity.

The conventional vibrating gyroscope has the drawback that the vibratingcharacteristics of the vibrating gyroscope may change or drift inresponse to the change of the ambient atmosphere. This is because thepiezoelectric elements detect a stress other than the Coriolis force dueto the differences of the thermal expansion coefficients among thevibrating member, the piezoelectric elements and the adhesive.

SUMMARY OF THE INVENTION

It is therefore, an object of the present invention to provide avibrating gyroscope free from the above-described problem and capable ofaccurately detecting the rotational angular velocity even if the ambientatmosphere temperature such as the ambient atmosphere temperature,changes.

To achieve the above-described object, according to the presentinvention, there is provided a vibrating gyroscope comprising acolumn-like vibratable body having a plurality of side surfaces, aplurality of piezoelectric elements each formed on a respective sidesurface of the vibratable body and having the same vibrationcharacteristics, a detection circuit having two input terminalsconnected to two detecting piezoelectric elements to detect thedifference between output signals from the two detecting piezoelectricelements, and supporting members attached to the vibrating body in thevicinity of nodal points of the vibrating body to support the vibratingbody, wherein the two detecting piezoelectric elements are the two ofthe plurality of detecting piezoelectric elements which provide thesmallest difference between their outputs with respect to a change inambient atmosphere temperature.

More specifically, the vibrating gyroscope may comprise a plurality ofconnection terminals connected to the plurality of piezoelectricelements, and two lead wires having ends connected to two inputterminals of the detection circuit and having opposite ends connected toselected two of the plurality of connection terminals, the detectingpiezoelectric elements and the input terminals of the detection circuitbeing connected through the connection terminals and the lead wires.

Also, the vibrating gyroscope may comprise a plurality of connectionterminals connected to the plurality of piezoelectric elements, and achange-over switch capable of changing the connection between theplurality of connection terminals and two input terminals of thedetection circuit, the detecting piezoelectric elements and the inputterminals of the detection circuit being connected through theconnection terminals and the change-over switch.

In the vibrating gyroscope arranged as described above, any of thepiezoelectric elements may be used as a detecting piezoelectric elementsince all the piezoelectric elements have the same vibrationcharacteristics. In the conventional vibrating gyroscope, the directionof self-excited vibration of the vibrating body is fixed at onedirection. However, since supporting members attached to the vibratingbody in the vicinity of nodal points of the vibrating body do notlargely impede the vibration of the vibrating body, there is noconsiderable problem even if the direction of self-excited vibration ofthe vibrating body is changed according to the positions of thedetecting piezoelectric elements. Therefore, it is possible to selecttwo detecting piezoelectric elements from the plurality of piezoelectricelements even after the vibrating body has been supported by thesupporting members without previously determining the positions ofdetecting piezoelectric elements. If a combination of two detectingpiezoelectric elements is selected such that the difference between theoutputs with respect to a change in ambient atmosphere temperature issmallest, it is possible to accurately detect the rotational angularvelocity even if the ambient atmosphere temperature changes.

In the case of the vibrating gyroscope having a plurality of connectionterminals connected to the plurality of piezoelectric elements and twolead wires having their ends connected to two input terminals of thedetection circuit and having their opposite ends connected to selectedtwo of the plurality of connection terminals, the detectingpiezoelectric elements connected to the input terminals of the detectioncircuit can be freely selected by changing the wiring using the leadwires.

Further, in the case of the vibrating gyroscope having a plurality ofconnection terminals connected to the plurality of piezoelectricelements, and a change-over switch capable of changing the connectionbetween the plurality of connection terminals and two input terminals ofthe detection circuit, the detecting piezoelectric elements connected tothe input terminals of the detection circuit can be freely selected bychanging the change-over switch.

For the purpose of illustrating the invention, there is shown in thedrawings several forms which are presently preferred, it beingunderstood, however, that the invention is not limited to the precisearrangements and instrumentalities shown.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an essential portion representing avibrator portion of a conventional vibrating gyroscope.

FIG. 2 is a front view of an essential portion representing the vibratorportion of the vibrating gyroscope shown in FIG. 1.

FIG. 3 is a perspective view of an essential portion representing avibrator portion of a vibrating gyroscope in accordance with a firstembodiment of the present invention.

FIG. 4 is a front view of the essential portion representing thevibrator portion of the vibrating gyroscope shown in FIG. 3.

FIG. 5 is a diagram showing a jig used to select detecting piezoelectricelements.

FIG. 6 is a circuit diagram showing one connected relationship betweenpiezoelectric elements, a drive circuit and a detection circuit.

FIG. 7 is a circuit diagram showing another connected relationshipbetween the piezoelectric elements, the drive circuit and the detectioncircuit.

FIG. 8 is a circuit diagram showing a further connected relationshipbetween the piezoelectric elements, the drive circuit and the detectioncircuit.

FIG. 9 is a circuit diagram of an essential portion of a vibratinggyroscope in accordance with a second embodiment of the presentinvention.

FIGS. 10A to 10C are diagrams in which the piezoelectric elements, thedrive circuit and the detection circuit are connected through lead wiresin the vibrating gyroscope shown in FIG. 9.

FIG. 11 is a diagram of a case in which the piezoelectric elements, thedrive circuit and the detection circuit are connected throughchange-over switches in the vibrating gyroscope shown in FIG. 9.

FIG. 12 is a perspective view of a vibrating gyroscope in accordancewith a third embodiment of the present invention.

FIG. 13 is another perspective view of a vibrating gyroscope inaccordance with the third embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, the preferred embodiments of the present invention areexplained in detail with reference to the drawings.

Embodiment 1

FIGS. 3 and 4 illustrate a vibrator portion 1 of a vibrating gyroscope,including a vibrating body 3. The vibrating body 3 is made of, forexample, a permanently elastic metal such as elinvar or a material suchas quartz, glass, crystal or ceramic capable of vibrating mechanicallyand is formed into substantially the same shape as a regular triangularprism. Piezoelectric elements 5a, 5b, 5c identical to each other invibrating characteristics and in shape are formed on side surfaces ofthe vibrating body 3. Each of the piezoelectric elements 5a, 5b, 5c ismade by forming electrodes on two surfaces of a piezoelectric ceramicmember and one of these electrodes is bonded to the side surface of thevibrating body 3 with an adhesive or the like.

Two supporting members 7, each of which is a generally square bottomedU-shaped member in the form of a wire rod having a high elastic modulus,e.g., a tungsten wire rod, are fixed to the vibrating body 3 in thevicinity of nodal points of the vibrating body 3 by means of welding orthe like. Ends of the supporting members 7 are fixed by means ofsoldering or the like to one major surface of a generally rectangularmount base plate 9 made of a glass-epoxy material or the like. Threeland electrodes 11a, 11b, 11c are formed on the one major surface of themount base plate 9 and are connected to the piezoelectric elements 5a,5b, 5c by lead wires 13. These land electrodes 11a, 11b, 11c are alsoconnected to three lead terminals 15a, 15b, 15c provided at one end ofthe mount base plate 9 in the lengthwise direction.

In the vibrating gyroscope having the thus-arranged vibrator portion 1,two of the three piezoelectric elements 5a, 5b, 5c are used for drivingand detection while the other one is used for feedback. A drive circuit(not shown in FIGS. 3 and 4) is connected between the drivingpiezoelectric elements and the feedback piezoelectric element as afeedback loop for causing self-excited vibration of the vibrating body3. The drive circuit is formed of an oscillation circuit and a phasecircuit. A detection circuit formed of a differential amplifier circuitis connected to the detecting piezoelectric elements. In this case, asexplained below in detail, two of the three piezoelectric elements areselected as detecting piezoelectric elements such that the differencebetween the outputs with respect to a change in ambient atmospheretemperature is smallest.

A method of selecting the detecting piezoelectric elements in thisvibrating gyroscope will next be described. First, a jig 30, such asthat shown in FIG. 5, is prepared. The jig 30 has a drive circuit 31, adetection circuit 33, terminals 34a, 34b which serve both as two outputterminals of the drive circuit 31 and as two input terminals of thedetection circuit 33, and a terminal 34c which serves as an inputterminal of the drive circuit 31. Lead wires 35a, 35b, 35c having plugs41a, 41b, 41c at their respective ends are connected to the terminals34a, 34b, 34c, respectively. Also, the jig 30 has three first connectionterminals 37a, 37b, 37c capable of being fitted to the plugs 41a, 41b,41c of the lead wires 35a, 35b, 35c, and second connection terminals39a, 39b, 39c to which the lead terminals 15a, 15b, 15c of the vibratorportion 1 can be coupled. The first connection terminals 37a, 37b, 37cand the second connection terminals 39a, 39b, 39c are connected to eachother.

The lead terminals 15a, 15b, 15c of the vibrator portion 1 arerespectively fitted to the second connection terminals 39a, 39b, 39c ofthe jig 30 to attach the vibrator portion 1 to the jig 30. Then theplugs 41a, 41b, 41c of the lead wires 35a, 35b, 35c are respectivelyfitted to the first connection terminals 37a, 37b, 37c. Thepiezoelectric elements are thereby connected as shown in FIG. 6; thepiezoelectric elements 5a, 5b of the vibrator portion 1 are respectivelyconnected to the two output terminals of the drive circuit 31 and to thetwo input terminals of the detection circuit 33 while the piezoelectricelement 5c is connected to the input terminal of the drive circuit 31,thereby causing self-excited vibration of the vibrating body 3 in adirection CT which is the result of combining the driving directions ofthe piezoelectric elements 5a, 5b for driving.

Next, after phase and level adjustment of drive signals of the drivecircuit 31, outputs of the piezoelectric elements 5a, 5b for detectionare measured while the vibrating body 3 is being heated, for example,with a drier or the like. Alternatively, the phase and level adjustmentmay be omitted. In such a case, outputs of the piezoelectric elements 5aand 5b, 5b and 5c, 5c and 5a are first measured at the room temperaturewhile vibrating the vibrating body 3 in a direction CT, L, and R,respectively. Then, the vibrating body 3 is kept heated with a drier orthe like and outputs of the piezoelectric elements 5a and 5b, 5b and 5c,and 5c and 5a are again measured at the high temperature while vibratingthe vibrating body in a direction CT, L, and R, respectively.

Thereafter, the vibrating body 3 is cooled to restore the state of thevibrating body 3 at the room temperature.

Next, the plugs 41a, 41b, 41c of the lead wires 35a, 35b, 35c aredetached from the first connection terminals 37a, 37b, 37c. Then theplug 41a is fitted to the first connection terminal 37c; the plug 41b tothe first connection terminal 37b; and the plug 41c to the firstconnection terminal 37a. The piezoelectric elements are therebyconnected as shown in FIG. 7; the piezoelectric elements 5b, 5c of thevibrator portion 1 are respectively connected to the two outputterminals of the drive circuit 31 and to the two input terminals of thedetection circuit 33 while the piezoelectric element 5a is connected tothe input terminal of the drive circuit 31, thereby causing self-excitedvibration of the vibrating body 3 in a direction L which is the resultof combining the driving directions of the piezoelectric elements 5b, 5coperated for driving.

Next, after phase and level adjustment of drive signals of the drivecircuit 31, outputs of the piezoelectric elements 5b, 5c operated fordetection are measured while the vibrating body 3 is being heated, forexample, with a drier or the like. Thereafter, the vibrating body 3 iscooled to restore the state of the vibrating body 3 at the roomtemperature.

Next, the plugs 41a, 41b, 41c of the lead wires 35a, 35b, 35c aredetached from the first connection terminals 37c, 37a, 37b. Then theplug 41a is fitted to the first connection terminal 37a; the plug 41b tothe first connection terminal 37c; and the plug 41c to the firstconnection terminal 37b. The piezoelectric elements are therebyconnected as shown in FIG. 8; the piezoelectric elements 5a, 5c of thevibrator portion 1 are respectively connected to the two outputterminals of the drive circuit 31 and to the two input terminals of thedetection circuit 33 while the piezoelectric element 5b is connected tothe input terminal of the drive circuit 31, thereby causing self-excitedvibration of the vibrating body 3 in a direction R which is the resultof combining the driving directions of the piezoelectric elements 5a, 5coperated for driving.

Next, after phase and level adjustment of drive signals of the drivecircuit 31, outputs of the piezoelectric elements 5a, 5c operated fordetection are measured while the vibrating body 3 is being heated, forexample, with a drier or the like. Thereafter, the measured outputs ofthe three combinations are compared to select the combination with theminimum differential output as determined detecting piezoelectricelements. This means that the direction of vibration of the vibratingbody 3 is selected by determining which of the piezoelectric elements5a, 5b, 5c is used for feedback. In this way, two of the piezoelectricelements 5a-5c are determined so as to work as a driving and detectingelement and the remaining one of the piezoelectric elements 5a-5c isdetermined so as to work as a feedback element.

The following table shows experimental results of ten samples obtainedby the aforementioned method. In the table, drifts of the vibratingcharacteristics were measured between -40° C. and 85° C. Data shown withan asterisk represent the smallest value obtained in the threedirections and means that that direction of vibration should be chosenfor the preferable direction of vibration.

                  TABLE                                                           ______________________________________                                        Drift (deg./sec.) in the                                                                             Preferable direction                                   specific direction of vibration                                                                      of vibration                                           Sample No.                                                                            L        CT       R      Direction                                                                            Drift                                 ______________________________________                                        1       12.3     5.0*     13.6   CT     5.0                                   2       9.9      5.7*     11.5   CT     5.7                                   3       5.3      1.8*     7.2    CT     1.8                                   4       5.0*     11.3     12.1   L      5.0                                   5       5.7*     8.5      10.1   L      5.7                                   6       1.8*     11.7     9.6    L      1.8                                   7       7.9      10.4     4.5*   R      4.5                                   8       8.2      7.8      1.3*   R      1.3                                   9       10.8     12.3     5.1*   R      5.1                                   10      11.1     8.9      4.2*   R      4.2                                   Average          8.3                    4.0                                   Standard         3.2                    1.3                                   Deviation                                                                     ______________________________________                                    

As is apparent from the table, if the ten vibrating gyroscopes are madevibrating in the same direction, for example, direction of CT, withoutchoosing a preferable direction based on the measured smallest drift,the average value on the drift becomes 8.3 deg/sec. On the other hand,if the ten vibrating gyroscopes are made vibrating in the respectivedirections selected based on the measured smallest drift, the averagevalue on the drift becomes 4.0 deg/sec.

Embodiment 2

According to the aforementioned Embodiment 1, three types of thevibrator portion 1 are manufactured depending on which piezoelectricelement of the three is used for feedback. Thus, lead terminals 15a-15cshown in FIG. 3 must be electrically connected to the driving circuitand the detection circuit in accordance with the types of the vibratorportion 1. This means that three types of a circuit board which receivesthe vibrator portion 1 and has a driving circuit and the detectioncircuit must be prepared. However, the preparation of circuit boardscorresponding to the different vibrator portions 1 entails a problem interms of cost and management. An embodiment of a vibrating gyroscope inwhich one circuit board is adaptable to three types of vibrator portion1 will now be described with reference to the drawings.

FIG. 9 illustrates a vibrating gyroscope 80 having a vibrator portion 1and a circuit board 81. The vibrator portion 1 is identical to thevibrator portion 1 shown in FIG. 3. The circuit board 81 includes adrive circuit 51, a detection circuit 53, terminals 55a, 55b, 55c andconnection terminals 57a, 57b, 57c. The terminals 55a and 55b areelectrically connected to both the drive circuit 51 and detectioncircuit 53 and serve both as output terminals of the drive circuit 51and as input terminals of the detection circuit 53. The terminal 55c isalso electrically connected to the drive circuit 51 and serves as aninput terminal of the drive circuit 53. The connection terminals 57a,57b, and 57c are respectively connected to lead terminals 15a, 15b, and15c of the vibrator portion 1. These components are formed on thecircuit board 81.

In one embodiment of the present invention, a wiring is formed by leadwires between the terminals 55a, 55b, 55c and the connection terminals57a, 57b, 57c according to each of the three types of vibratorportion 1. That is, if the piezoelectric elements 5a, 5b are used fordriving and detection while the piezoelectric element 5c is used forfeedback, each of the pair of the terminal 55a and the connectionterminal 57a, the pair of the terminal 55b and the connection terminal57b and the pair of the terminal 55c and the connection terminal 57c areconnected by lead wire 61, as shown in FIG. 10A. If the piezoelectricelements 5b, 5c are used for driving and detection while thepiezoelectric element 5a is used for feedback, each of the pair of theterminal 55a and the connection terminal 57c, the pair of the terminal55b and the connection terminal 57b and the pair of the terminal 55c andthe connection terminal 57a are connected by lead wire 61, as shown inFIG. 10B. Further, if the piezoelectric elements 5a, 5c are used fordriving and detection while the piezoelectric element 5b is used forfeedback, each of the pair of the terminal 55a and the connectionterminal 57a, the pair of the terminal 55b and the connection terminal57c and the pair of the terminal 55c and the connection terminal 57b areconnected by lead wire 61, as shown in FIG. 10C.

As understood from the above-explanation, by connecting terminals 55a,55b, 55c and the connection terminals 57a, 57b, 57c using lead wires,the piezoelectric elements 5c, 5a and 5b of the vibrator portion 1 areselectively connected with a drive circuit and a detection circuit sothat predetermined one of the piezoelectric elements 5c, 5a and 5b isused for feedback. Thus, one circuit board is adaptable to three typesof vibrator portion in which vibrating body vibrate in differentdirections, thereby reducing the production cost.

As alternative embodiment shown in FIG. 11, change-over switches 62a,62b, 62c may be respectively provided between the terminals 55a, 55b,55c and the connection terminals 57a, 57b, 57c instead of using wiring.If the piezoelectric elements 5a, 5b are used for driving and detectionwhile the piezoelectric element 5c is used for feedback, each of thepair of the terminal 55a and the connection terminal 57a, the pair ofthe terminal 55b and the connection terminal 57b and the pair of theterminal 55c and the connection terminal 57c are connected by operatingthe change-over switches 62a, 62b, 62c. If the piezoelectric elements5b, 5c are used for driving and detection while the piezoelectricelement 5a is used for feedback, each of the pair of the terminal 55aand the connection terminal 57c, the pair of the terminal 55b and theconnection terminal 57b and the pair of the terminal 55c and theconnection terminal 57a are connected by operating the change-overswitches 62a, 62b, 62c. Further, if the piezoelectric elements 5a, 5care used for driving and detection while the piezoelectric element 5b isused for feedback, each of the pair of the terminal 55a and theconnection terminal 57a, the pair of the terminal 55b and the connectionterminal 57c and the pair of the terminal 55c and the connectionterminal 57b are connected by operating the change-over switches 62a,62b, 62c.

Embodiment 3

FIGS. 12 and 13 are perspective views of a vibrating gyroscope inaccordance with a third embodiment of the present invention. Thevibrating gyroscope 90 shown in FIG. 12 includes a vibrator portion 91and a circuit board 93. The vibrating gyroscope 90' shown in FIG. 13also includes a vibrator portion 91' and a circuit board 93, but thevibrator portion 91' shown in FIG. 13 is positioned rotated by 180degrees with respect to the circuit board 93.

The vibrator portion 91 (or 91') is identical to the vibrator portion 1except that the vibrator portion 91 (or 91') has lead terminalconnecting portions 94, 95, 96 formed on the mount base plate 9 insteadof lead terminals 15a, 15b, 15c. Each of the lead terminal connectingportions 94, 95, 96 consists of three connecting electrodes, namely,connecting electrodes 94a-94c, 95a-95c, and 96a-96c. The connectingelectrodes 94a, 95a, 96a are electrically connected to the landelectrodes 11a via a conductive pattern (not shown in FIGS. 12 and 13for the sake of clarity) formed on the front surface and rear surface ofthe mount base plate 9. The connecting electrodes 94b, 95b, 96b and 94c,95c, 96c are also electrically connected to the land electrodes 11b and11c, respectively.

The circuit board 93 includes a drive circuit, a detection circuit andterminals 55a, 55b, 55c formed thereon, respectively. The drive circuitand detection circuit are not shown in FIGS, 12 and 13 for the sake ofclarity but are electrically connected to the terminals 55a, 55b, 55c asshown in FIG. 9. As is explained above, the terminal 55c is used forconnecting the drive circuit and the piezoelectric element for feedback.The terminals 55a, 55b, 55c are located at the vicinity of a side of thecircuit board 93. Two holes or through holes are provided with each ofthe terminals 55a, 55b, 55c so as to receive lead wires.

The lead terminal connecting portions 94 are located along and at thevicinity of one of opposite two sides of the mount base plate 9, whilethe lead terminal connecting portions 95, 96 are located along and atthe vicinity of the other of opposite two sides of the mount base plate9. More specifically, as shown in FIG. 12, the connecting electrodes94a-94c of the lead terminal connecting portions 94 are located on themount base plate 9 at a predetermined distance so as to position abovethe terminals 55a, 55b, 55c in the case where the vibrator portion 91and a circuit board 93 are coupled via the lead wires. Moreover, asshown in FIG. 13, the connecting electrodes 95a-95c and 96a-96c arerespectively located on the mount base plate 9 at a predetermineddistance so at to be positioned above the terminals 55a, 55b, 55c in thecase where the vibrator portion 91 is rotated by 180 degrees withrespect to the circuit board 93 from the configuration shown in FIG. 12.Thus, the connecting electrodes 94c, 95a, 96b can be positioned abovethe terminal 55c and connected via lead wires 97. Since the connectingelectrodes 94c, 95a, 96b are respectively connected to the piezoelectricelements 5c, 5a, 5b and the terminal 55c is used for feedback, either ofthe piezoelectric elements 5c, 5a, 5b can be used for feedback and theremaining two of the piezoelectric elements 5c, 5a, 5b can be used fordetection.

As understood from the above-explanation, by using the lead terminalconnecting portions 94, 95 and 96, the piezoelectric elements 5c, 5a and5b of the vibrator portion 91 (or 91') are selectively connected with adrive circuit and a detection circuit so that predetermined one of thepiezoelectric elements 5c, 5a and 5b is used for feedback.

The vibrating gyroscope 91 (or 91') is manufactured for example, by thefollowing process. First, the vibrating body 3 is prepared and thepiezoelectric elements 5a-5c are disposed on a side faces of thevibrating body 3. Two supporting members 7 each of which is a generallysquare bottomed U-shape member in the form of a wire rod having a highelastic modulus, e.g., a tungsten wire rod are then fixed to thevibrating body 3 in the vicinity of nodal points of the vibrating body 3by means of welding or the like. Ends of the supporting members 7 arefixed by means of soldering or the like to one major surface of a mountbase plate 9 on which land electrodes 11a-11c and the connectingelectrodes 94a-94c, 95a-95c, and 96a-96c are formed. Note that one ofthe essential features of the present invention is that the vibratingdirection of the vibrating body 3 can be selected after the vibratingbody 3 is fixed to the supporting members 7. Thus, it is not required tomeasure any physical properties which indicate or represent a preferablevibrating direction of the vibrating body 3 before fixing the vibratingbody 3 to the supporting member 7.

Thereafter, vibrator portion 91 (or 91') manufactured by theaforementioned steps is examined so as to determine the which of thepiezoelectric elements 5a-5c should be used for feedback using the jig30 as explained above referring to FIG. 5.

Then, the vibrating portion 91 (or 91') is mounted on the circuit board93 having a drive circuit, a detection circuit and terminals 55a, 55b,55c thereon. Specifically, if the piezoelectric elements 5c should beused for feedback, the vibrating portion 91 is so located that theconnecting electrodes 94a-94c are positioned corresponding to theterminals 55a-55c, and the connecting electrodes 94a-94c and theterminals 55a-55c are electrically connected via lead wires 97, as shownin FIG. 12. On the other hand, if the piezoelectric elements 5a shouldbe used for feedback, the vibrating portion 91' is so located that theconnecting electrodes 95a-95c are positioned corresponding to theterminals 55a-55c, and the connecting electrodes 95a-95c and theterminals 55a-55c are electrically connected via lead wires 97, as shownin FIG. 13. It is appreciated that the connecting electrodes 96a-96cshould be selected in the case where the piezoelectric elements 5b isused for feedback.

In the thus-constructed vibrating gyroscope, a combination of twodetecting piezoelectric elements is selected such that the differencebetween the outputs with respect to a change in ambient atmospheretemperature is smallest, thereby making it possible to accurately detectthe rotational angular velocity even if the ambient atmospheretemperature changes.

Each of the embodiments has been described with respect to the casewhere one piezoelectric element is used both for drive and detection.However, the present invention is not limited to this, and drivingpiezoelectric elements may be provided independently of detectingpiezoelectric elements.

The vibrating body has been described as a member having the shape of atriangular prism. However, the vibrating member may have any shape otherthan the triangular prism, e.g., a polygonal prism or a cylinder. Also,the number of piezoelectric elements formed on side surfaces of thevibrating body is not limited.

In the vibrating gyroscope of the present invention, as described above,a combination of two detecting piezoelectric elements such that thedifference between the outputs with respect to a change in ambientatmosphere temperature is smallest is selected after the vibrating bodyhas been supported by supporting members, thereby making it possible toaccurately detect the rotational angular velocity even if the ambientatmosphere temperature changes.

While preferred embodiments of the invention have been disclosed,various modes of carrying out the principles disclosed herein arecontemplated as being within the scope of the following claims.Therefore, it is understood that the scope of the invention is not to belimited except as otherwise set forth in the claims.

What is claimed is:
 1. A method for producing a vibrating gyroscope,comprising the steps of:(a) providing a column-like vibratable bodyhaving at least three piezoelectric elements each formed on a sidesurface of the vibratable body; (b) mounting the vibratable body withsupporting members coupled with a mount base such that the vibratablebody is supported by the supporting members at the vicinity of nodalpoints of the vibrating body; (c) selecting two from the at least threepiezoelectric elements as a combination of detecting piezoelectricelements such that a drift of the difference between outputs from thetwo with respect to a change in ambient atmosphere is smallest; and (d)electrically connecting the at least three piezoelectric elements with adetection circuit and a drive circuit based on the selection of theselecting step.
 2. A method for producing a vibrating gyroscopeaccording to claim 1, wherein the change in ambient atmosphere is achange in ambient temperature.
 3. A method for producing a vibratinggyroscope according to claim 2, wherein the step (c) comprises the stepsof:(c1) measuring the drift with respect to each combination of pairs ofthe piezoelectric elements within a predetermined temperature range; and(c2) determining between which pair of piezoelectric elements the driftis the smallest.
 4. A method for producing a vibrating gyroscopeaccording to claim 3, wherein the step (c1) comprises the stepsof:measuring differences between the outputs from a first pair of thepiezoelectric elements at first and second predetermined temperatures todetermine the drift between the first and second predeterminedtemperatures; and measuring differences between the outputs from theother pairs of the piezoelectric elements at the first and secondpredetermined temperature to determine the drift between the first andsecond predetermined temperatures.
 5. A method for producing a vibratinggyroscope, comprising the steps of:(a) providing a column-likevibratable body having at least two pairs of piezoelectric elements eachformed on a side surface of the vibratable body; (b) mounting thevibratable body with supporting members coupled with a mount base suchthat the vibratable body is supported by the supporting members at thevicinity of nodal points of the vibrating body; and (c) electricallyconnecting the at least two pairs of piezoelectric elements with adetection circuit and a drive circuit such that the vibratable bodyvibrates in a predetermined direction based on results obtained bymeasuring temperature characteristics of the piezoelectric elements. 6.A method for producing a vibrating gyroscope according to claim 5,wherein the step (c) comprises the steps of:measuring a drift of thedifferences between outputs from each pair of the piezoelectricelements, selected as a combination of detecting piezoelectric elements,within a predetermined temperature range; determining between which pairof piezoelectric elements the drift is the smallest; and determining theelectrical connection between the piezoelectric elements and thedetection and drive circuits which allows the vibratable body to vibratein the predetermined direction such that the determined pair ofpiezoelectric elements work as detecting piezoelectric elements.